1. Field of the Invention
The present invention relates to a substrate processing method, a substrate processing apparatus and a substrate carrying method.
2. Description of the Related Art
In a photolithography process in fabrication processes for the semiconductor device, for example, resist coating treatment for forming a resist film on a wafer surface, exposure processing in which a pattern is irradiated on the wafer and exposed, post-exposure baking treatment for heating the wafer after the exposure processing, developing treatment for performing development for the heat-treated wafer and the like are performed in sequence. These processing and treatments are sequentially performed in processing and treatment units separately provided in a single coating and developing treatment system and an aligner adjacent to the system. The coating and developing treatment system is structured to process a plurality of wafers concurrently at the same time, in which normally one carrier carries the wafers between the above-mentioned processing and treatment units.
The carrier is configured to freely access the plurality of processing and treatment units and its operation is controlled to carry the wafers in the processing and treatment units at preferable timing in accordance with the processing steps to the processing and treatment units in which the respective following steps are performed, so that a series of the photolithography processing steps is smoothly performed.
However, one carrier carries a number of wafers as described above, and thus in the case where, for example, when the carrier is carrying one wafer in one processing or treatment unit, treatment for another wafer is completed in another processing or treatment unit, the carrier can not carry the other wafer before it finishes carrying the one wafer. Meanwhile, when the carrier is not carrying a wafer but in a waiting state, the carrier can immediately carry the other wafer. Accordingly, the period required after the treatment for a wafer finishes and before the carrier goes to receive the wafer depends on the position and the state of the carrier, presenting a fear that the total periods required from the end of one treatment to the start of the following treatment become nonuniform between the wafers.
When a so-called chemically amplified resist is used as a resist solution for forming the aforementioned resist film, exposure generates acid, and the resist film reacts with the acid and the resist film in the exposed portion changes to be soluble in the developing solution. Therefore, the degree of the developing treatment, that is, the line width of the circuit pattern on the wafer, greatly depends on progress of the chemical reaction by the acid, and the chemical reaction is greatly affected by the period from the exposure to the development.
Accordingly, the period after the wafer is subjected to the exposure processing and before the developing treatment, especially, the period required from the exposure processing to the post-exposure baking treatment is affected by the position and the state of the carrier to be nonuniform, presenting a fear of adversely affecting the line of the circuit pattern which is finally formed on the wafer.
Further, the aforementioned carrying of the wafer is conducted as follows, normally a main controller for controlling the carrier receives a processing end signal from each processing or treatment unit and stores it, the carrier recognizes the stored processing end signal every completion of the carrying of one wafer, and the carrier verifies it and then moves to the processing or treatment unit that is the sender to carry the wafer for which predetermined processing has been completed in the processing or treatment unit to the processing or treatment unit where the following step is performed.
According to the above-described control mechanism for the carrier, however, since the carrier finishes the carrying of the present wafer and verifies processing end signal in the main controller, and then moves to the processing or treatment unit that is the sender, the period after the processing or treatment for the wafer finishes in the processing or treatment unit and before the carrier goes to the processing or treatment unit to receive the wafer differs depending on the state of the carrier at the moment or the number of the processing end signals, and generally tends to be longer. Therefore, it is impossible to carry the wafer between the processing and treatment units speedily and in a fixed period.
Especially when the chemically amplified resist solution is used as described above, a treatment is performed in which the acid, as a catalyst, generated in the resist film by the exposure is increased in temperature to activate, promoting the chemical reaction for making the resist film soluble in the developing solution in the post-exposure baking treatment. In the following cooling treatment, a treatment of decreasing the acid in temperature to stop the catalysis of the acid is performed. Therefore, unless the wafer is speedily carried between the post-exposure baking unit and the cooling treatment unit, the wafer is overbaked to cause the chemical reaction to excessively proceed by the catalysis of the acid to widen the width of the resist film soluble in the developing solution, resulting in too wide line width of the circuit pattern which is finally formed on the wafer. Furthermore, if the wafer is not carried between the post-exposure baking unit and the cooling treatment unit in a fixed manner, there is a fear that line widths of the circuit patterns formed on wafers will become nonuniform between the wafers.
The present invention is made in view of the above-described points, and its object is to fix the period required, for example, from exposure processing to post-exposure baking treatment, that is, to heat treatment before developing treatment in a photolithography process, or to make an improvement to make the period close to fixed.
Further, a second object of the present invention is to shorten the period after the completion of heat treatment and before the substrate is cooled and to fix the period.
The present invention is a method of performing processing for a substrate including the step of carrying the substrate, which has been pre-treated, to a heat treatment unit for heating the substrate, prior to supplying a treatment solution to the substrate to perform solution treatment, wherein the carrying is performed such as to fix a period after the pretreatment for the substrate is completed and before the substrate is carried to the heat treatment unit.
According to another aspect, the present invention is a method of performing processing for a substrate including the step of carrying the substrate, which has been exposure-processed, to a heat treatment unit where heat treatment before developing treatment is performed, wherein the carrying is performed such as to fix a period after the exposure processing for the substrate is completed and before the substrate is carried to the heat treatment unit.
According to still another aspect, the present invention is a method of performing processing for a substrate including the steps of carrying the substrate, which has been exposure-processed, temporarily to a delivery unit by a first carrier, and thereafter carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, by a second carrier, wherein at least when the exposure for the substrate is completed, the first carrier is waiting at a first position where the first carrier is capable of receiving the exposed substrate to immediately carry the substrate, for which the exposure has been completed, to the delivery unit, and wherein at least when the exposed substrate is carried to the delivery unit, the second carrier is waiting at a second position where the second carrier is capable of receiving the substrate staying in the delivery unit to carry the substrate to the heat treatment unit immediately after the exposed substrate is carried to the delivery unit.
According to yet another aspect, the present invention is a method of performing processing for a substrate including the steps of carrying the substrate, which has been exposure-processed, temporarily to a delivery unit by a first carrier, and thereafter carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, by a second carrier, wherein at least when the exposure processing for the substrate is completed, the first carrier is waiting at a predetermined position where the first carrier is capable of receiving the substrate to carry the substrate to the delivery unit immediately after the exposure processing for the substrate is completed.
According to further another aspect, the present invention is a method of performing processing for a substrate including the steps of carrying the substrate, which has been exposure-processed, temporarily to a delivery unit by a first carrier, and thereafter carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, by a second carrier, wherein at least when the substrate is carried to the delivery unit, the second carrier is waiting at a predetermined position where the second carrier is capable of receiving the substrate to carry the substrate to the heat treatment unit immediately after the substrate is carried to the delivery unit.
The apparatus of the present invention is a substrate processing apparatus for performing processing for a substrate including a carrier for carrying the substrate, which has been pre-treated, to a heat treatment unit for heating the substrate prior to solution treatment performed by supplying a treatment solution to the substrate, and a controller for controlling the carrier such as to fix a period after the pretreatment for the substrate is completed and before the substrate is carried to the heat treatment unit.
According to another aspect, the present invention is a substrate processing apparatus for performing processing for a substrate including a carrier for carrying the substrate, which has been exposure-processed, to a heat treatment unit where heat treatment before developing treatment is performed, and a controller for controlling the carrier such as to fix a period after the exposure processing for the substrate is completed and before the substrate is carried to the heat treatment unit.
According to still another aspect, the present invention is a substrate processing apparatus for performing processing for a substrate including a first carrier for carrying the substrate, which has been exposure-processed, to a delivery unit, a second carrier for carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, and a controller for controlling the first carrier and the second carrier, wherein the controller conducts a control so that at least when the exposure processing for the substrate is completed, the first carrier is waiting at a first position where the first carrier is capable of receiving the exposed substrate to immediately carry the substrate, for which the exposure processing has been completed, to the delivery unit, and further at least when the exposure-processed substrate is carried to the delivery unit, the second carrier is waiting at a second position where the second carrier is capable of receiving the substrate staying in the delivery unit to carry the substrate to the heat treatment unit immediately after the exposure-processed substrate is carried to the delivery unit.
According to yet another aspect, the present invention is a substrate processing apparatus for performing processing for a substrate including a first carrier for carrying the substrate, which has been exposure-processed, to a delivery unit, a second carrier for carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, and a controller for controlling the first carrier and the second carrier, wherein the controller conducts a control so that at least when the exposure processing for the substrate is completed, the first carrier is waiting at a predetermined position where the first carrier is capable of receiving the substrate to carry the substrate to the delivery unit immediately after the exposure processing for the substrate is completed.
According to further another aspect, the present invention is a substrate processing apparatus for performing processing for a substrate including a first carrier for carrying the substrate, which has been exposure-processed, to a delivery unit, a second carrier for carrying the substrate staying in the delivery unit to a heat treatment unit where heat treatment before developing treatment is performed, and a controller for controlling the first carrier and the second carrier, wherein the controller conducts a control so that at least when the substrate is carried to the delivery unit, the second carrier is waiting at a predetermined position where the second carrier is capable of receiving the substrate to carry the substrate to the heat treatment unit immediately after the substrate is carried to the delivery unit.
Furthermore, in order to attain the second object, according to the present invention, in a substrate carrying method of carrying a substrate, which has been heat-treated in a heat treatment unit, by a carrier to a cooling treatment unit where cooling treatment for the substrate is performed, at least when the heat treatment for the substrate is completed, the carrier is waiting at a predetermined position where the carrier is capable of receiving the substrate in the heat treatment unit.
The present invention includes the step of carrying the substrate, which has been pre-treated, to a heat treatment unit for heating the substrate, prior to supplying a treatment solution to the substrate to perform solution treatment, wherein the carrying is performed such as to fix a period after the pretreatment for the substrate is completed and before the substrate is carried to the heat treatment unit.
According to the present invention, since the carrying of the substrate is performed such as to fix the period after the pretreatment for the substrate is completed and before it is carried to the heat treatment unit, for example, the substrate is carried such as to fix the period after the exposure processing that is the pretreatment and before it is carried to the heat treatment unit where heat treatment that is the following treatment, whereby the degrees of the chemical reaction of the coating films by the above-described exposure processing become uniform between substrates. Thus, the developing treatment is performed for the substrates at the same degree, uniformly forming the line widths of the circuit patterns which are finally formed on the substrates between substrates.
For example, the carrying such as to fix the period after the completion of the exposure processing for the substrate and before it is carried to the heat treatment unit is realized, for example, by controlling the operation of the carrier for carrying the substrate from the aligner to the heat treatment unit. More specifically, it is suggested that, for example, the carrier is kept waiting in front of the aligner in advance to carry the substrate to the heat treatment unit immediately after the exposure is completed and the substrate comes out of the aligner, the carrying of the substrate is always started after a lapse of a fixed period from the completion of the exposure processing, the carrier holding the substrate is suspended at a predetermined place and the suspension period in the event is adjusted, or the like.
Furthermore, according to the present invention, when the exposure processing for the substrate is completed, the first carrier is waiting at the first position where it can receive the substrate to carry the substrate to the delivery unit immediately after the completion of exposure for the substrate. Furthermore, when the substrate is carried to the delivery unit, the second carrier is waiting at the second position where it can receive the substrate to carry the substrate to the heat treatment unit immediately after the substrate is carried to the delivery unit. The first and second carriers wait at the respective predetermined positions preceding to the carrying of other substrates, eliminating the fact that the carriers are, for example, carrying the other substrates or have moved to the positions where they can not immediately receive the substrate, with the result that the carrying period for the substrate from the exposure processing to the heat treatment unit is kept fixed. Accordingly, the above-described chemical reaction of the solubilization in the developing solution uniformly proceeds, whereby the developing treatment is uniformly performed for the substrates, reducing nonuniformity in line width of the finally formed pattern between the substrates. It should be noted that the first carrier and the second carrier are preferably waiting at the respective predetermined positions at least when the exposure is completed and at least when the substrate is carried to the delivery unit respectively, and they may be previously waiting from a predetermined period before.
According to the present invention, the carrier is kept waiting from before the completion of the heat treatment at the predetermined position where it can receive the substrate in the heat treatment unit to receive the substrate immediately after the completion of the heat treatment and carry it to the cooling treatment unit. This shortens the period after the completion of the heat treatment and before the substrate is subjected to the cooling treatment and keeps the period fixed. Therefore, overbaking in the heat treatment and nonuniformity in pattern which is finally formed on the substrate between substrates are reduced.
The heat treatment unit gives notice of completion of the heat treatment to the carrier controller, and the carrier controller moves the carrier to the waiting position based on the notice, whereby the carrier can recognize at an earlier time that the heat treatment is immediately before completion, and move to the predetermined position before the completion of the heat treatment and wait there. Therefore, when the heat treatment is completed, the carrier can be waiting at the position where it can access the heat treatment unit and immediately carry the substrate, for which the heating has been completed, to the cooling treatment unit.
By giving discrimination marks to the substrates, when the carrier can not be waiting at the predetermined position at the completion of the heat treatment of the substrate, for example, when the carrier can not be waiting by the completion of the heat treatment because the carrier delays in moving to the predetermined position because of the carrying of another substrate, the substrate, which is presumed to be subjected to the heat treatment at the moment and made stand in a state of a high temperature for a period longer than the other substrates, can be recognized as a substrate needing caution based on its discrimination mark. This makes it possible to recognize the substrate of high possibility of being overbaked and remove the substrate needing caution from the other substrates when necessary. Note that the discrimination mark given to the substrate is not limited to one actually provided on the substrate, but it may be an imaginary discrimination mark, for example, a code which is recognized by a controller or the like to result in discrimination of each substrate.